Income, Geography, and Etiology as Factors Associated with Valve Replacement Outcomes: A Nationwide Cohort of 63,426 Patients in a Middle-Income Country

Background: Heart valve disease is a growing cause of mortality and disability worldwide, disproportionately burdening low- and middle-income countries (LMICs), where rheumatic heart disease remains a major etiology and cardiac surgical capacity covers less than 2% of the estimated need. Population-level outcome data after valve surgery in LMICs are virtually absent. We leveraged Brazil's universal health system to quantify how income, geography, and disease etiology are associated with survival after valve replacement surgery. Methods: Five Brazilian public health databases covering outpatient care (SIA), hospital admissions (SIH), mortality records (SIM), the cancer registry (RHC), and a social vulnerability index (IVS Atlas) were linked to a single individual-level longitudinal record, with a proof-of-life algorithm correcting right-censoring bias. All patients undergoing valve replacement surgery between January 2015 and December 2024 were included. Results: Among 63,426 patients (mean age 56.9 ± 15.2 years; median follow-up 1,023 days), the in-hospital mortality rate was 8.6% and the five-year mortality was 30.1%. Income and geography were significantly associated with survival: the highest income quartile had significantly lower mortality than the lowest quartile in the adjusted Cox model (HR 0.82; 95% CI 0.76-0.89; p < 0.001), and in-hospital mortality exceeded 25% in low-volume municipalities in the North region. Valve lesion subtype predicted outcomes differentially across time horizons, and reoperation was associated with worse survival (HR 1.48; 95% CI 1.37-1.58; p < 0.001). Conclusion: Income, geography, and valve-specific risk factors are important factors associated with survival after valve surgery in Brazil's public health system, reflecting structural conditions shared across LMICs. The linkage framework offers a scalable model for cardiovascular outcome surveillance in resource-constrained settings. Lay Summary: Each year, thousands of Brazilians undergo heart valve surgery through the public health system. Using data from over 63,000 patients treated between 2015 and 2024, we found that survival after valve surgery in Brazil is substantially worse than in wealthier countries and that outcomes differ markedly depending on which valve is affected and why. Patients who required a second surgery fared worse, and those living in regions with fewer surgical centers faced higher mortality. These findings highlight critical gaps in cardiac surgical care, which can guide resource allocation and policy in Brazil and similar settings.